discourse/plugins/chat/app/models
Martin Brennan 60ad836313
DEV: Chat service object initial implementation (#19814)
This is a combined work of Martin Brennan, Loïc Guitaut, and Joffrey Jaffeux.

---

This commit implements a base service object when working in chat. The documentation is available at https://discourse.github.io/discourse/chat/backend/Chat/Service.html

Generating documentation has been made as part of this commit with a bigger goal in mind of generally making it easier to dive into the chat project.

Working with services generally involves 3 parts:

- The service object itself, which is a series of steps where few of them are specialized (model, transaction, policy)

```ruby
class UpdateAge
  include Chat::Service::Base

  model :user, :fetch_user
  policy :can_see_user
  contract
  step :update_age

  class Contract
    attribute :age, :integer
  end

  def fetch_user(user_id:, **)
    User.find_by(id: user_id)
  end

  def can_see_user(guardian:, **)
    guardian.can_see_user(user)
  end

  def update_age(age:, **)
    user.update!(age: age)
  end
end
```

- The `with_service` controller helper, handling success and failure of the service within a service and making easy to return proper response to it from the controller

```ruby
def update
  with_service(UpdateAge) do
    on_success { render_serialized(result.user, BasicUserSerializer, root: "user") }
  end
end
```

- Rspec matchers and steps inspector, improving the dev experience while creating specs for a service

```ruby
RSpec.describe(UpdateAge) do
  subject(:result) do
    described_class.call(guardian: guardian, user_id: user.id, age: age)
  end

  fab!(:user) { Fabricate(:user) }
  fab!(:current_user) { Fabricate(:admin) }

  let(:guardian) { Guardian.new(current_user) }
  let(:age) { 1 }

   it { expect(user.reload.age).to eq(age) }
end
```

Note in case of unexpected failure in your spec, the output will give all the relevant information:

```
  1) UpdateAge when no channel_id is given is expected to fail to find a model named 'user'
     Failure/Error: it { is_expected.to fail_to_find_a_model(:user) }

       Expected model 'foo' (key: 'result.model.user') was not found in the result object.

       [1/4] [model] 'user' 
       [2/4] [policy] 'can_see_user'
       [3/4] [contract] 'default'
       [4/4] [step] 'update_age'

       /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/update_age.rb:32:in `fetch_user': missing keyword: :user_id (ArgumentError)
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:202:in `instance_exec'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:202:in `call'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:219:in `call'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:417:in `block in run!'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:417:in `each'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:417:in `run!'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:411:in `run'
       	from <internal:kernel>:90:in `tap'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:302:in `call'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/spec/services/update_age_spec.rb:15:in `block (3 levels) in <main>'
```
2023-02-13 13:09:57 +01:00
..
concerns
category_channel.rb FIX: Do not error if autogenerated channel slug is blank (#19759) 2023-01-06 09:04:52 +10:00
chat_channel_archive.rb FIX: Improve error reporting and failure modes for channel archiving (#19791) 2023-01-12 10:04:46 +10:00
chat_channel.rb DEV: Chat service object initial implementation (#19814) 2023-02-13 13:09:57 +01:00
chat_draft.rb SECURITY: Limit chat drafts length and preloaded count (#19987) 2023-01-25 13:50:10 +02:00
chat_mention.rb FIX: Delete associated notifications when trashing chat messages. (#20144) 2023-02-03 12:52:13 -03:00
chat_message_reaction.rb
chat_message_revision.rb FIX: Make chat editor IDs not null (#18903) 2022-11-08 09:06:13 +10:00
chat_message.rb DEV: correct a relationship – a chat message may have several mentions (#20219) 2023-02-09 17:44:04 +04:00
chat_thread.rb DEV: Add ChatThread model and DB table, and ChatMessage reference (#20106) 2023-02-01 13:50:38 +10:00
chat_upload.rb DEV: Use UploadReference instead of ChatUpload in chat (#19947) 2023-01-24 13:28:21 +10:00
chat_view.rb
chat_webhook_event.rb
deleted_chat_user.rb
direct_message_channel.rb FIX: Automatically generate category channel slugs (#18879) 2022-11-09 10:28:31 +10:00
direct_message_user.rb
direct_message.rb
incoming_chat_webhook.rb
reviewable_chat_message.rb FIX: Unsilence users on chat message flag disagree. (#19198) 2022-11-28 11:11:35 -03:00
user_chat_channel_membership.rb